In this section, we assess the performance of the proposed 2-D GLRT based detector/estimator in (REF ). The OTFS radar observations are generated using (REF ) instead of the proposed model in (REF ) to provide an implicit verification of the transition from (REF ) to (REF ). As a benchmark, we consider a standard 2-D FFT based processing traditionally employed in OFDM radar [1]}, [2]}. To evaluate detection performances for both GLRT and FFT methods, a cell-averaging CFAR detector is employed with the probability of false alarm \(P_{\rm {fa}}= 10^{-4}\)  to declare targets in the delay-Doppler domain. For a target with channel gain \(\alpha \) , we define the signal-to-noise ratio (SNR) as \({\rm {SNR}}= {\alpha }^2/\sigma ^2\) . In addition, a rectangular pulse shaping waveform is used for \(g_{\rm {tx}}(t)\)  in (REF ).
We consider two different parameter sets for OTFS, as shown in Table REF , to illustrate the results in both ISI-dominant (i.e., high \( \Delta f \) ) and ICI-dominant (i.e., small \( \Delta f \) ) operation regimes. In the ISI-dominant regime, maximum range is the limiting factor for radar detection performance, while in the ICI-dominant regime, radar performance is mainly limited by maximum velocity.
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